Inspecting CL_GUI_ALV_GRID in Transaction SE24

When working with Object-Oriented ALV (OOALV), the central class is CL_GUI_ALV_GRID. Understanding its definition in SE24 is crucial before implementation.

Class Attributes

Attributes in SE24 correspond to DATA (instance) or CLASS-DATA (static) in local classes. Pay attention to the Visibility (Public, Protected, Private) as it dictates accessibility. The Associated Type column indicates the data type; types containing _S_ typically represent structures, while _T_ indicates table types.

Methods

Instance methods (created with METHODS) require an object instance to be called, while static methods (CLASS-METHODS) can be called on the class itself. To analyze a method's logic, double-click its name in SE24 to view the implementation. Note that methods inherited from interfaces may appear with a wavy line prefix.

Events

Event are pivotal for interactivity. In SE24, you can see which parameters an event passes. A standard implicit parameter in ALV events is SENDER, which references the object that raised the event.

Aliases

Aliases provide shorthand names for interface methods, simplifying calls by avoiding the interface_name~method_name syntax.

Building an OOALV Report: Step-by-Step

The proces involves creating a container, instantiating the grid, and passing data.

1. Container and Grid Instantiation

OOALV requires a parent container. While CL_GUI_CONTAINER is the abstract base, CL_GUI_CUSTOM_CONTAINER is commonly used when a screen control is drawn in the Screen Painter.

The constructor of CL_GUI_CUSTOM_CONTAINER requires CONTAINER_NAME, which must match the name of the Custom Control defined on your screen (e.g., CUSTOM_01).

DATA: lo_container TYPE REF TO cl_gui_custom_container,
      lo_grid      TYPE REF TO cl_gui_alv_grid.

CREATE OBJECT lo_container
  EXPORTING
    container_name = 'CUSTOM_01'.

CREATE OBJECT lo_grid
  EXPORTING
    i_parent = lo_container.

2. Defining Data and Field Catalog

Define a local structure for your output data and an internal table.

TYPES: BEGIN OF ty_employee,
         id     TYPE string,
         name   TYPE string,
         dept   TYPE string,
         salary TYPE i,
       END OF ty_employee.

DATA: gt_employees TYPE TABLE OF ty_employee,
      gt_fcat      TYPE lvc_t_fcat.

Build the field catalog. You can use a macro or populate the LVC_S_FCAT structure manually.

FORM build_catalog .
  DATA: ls_fcat TYPE lvc_s_fcat.

  ls_fcat-fieldname = 'ID'.
  ls_fcat-coltext   = 'Employee ID'.
  APPEND ls_fcat TO gt_fcat.

  ls_fcat-fieldname = 'NAME'.
  ls_fcat-coltext   = 'Full Name'.
  APPEND ls_fcat TO gt_fcat.

  ls_fcat-fieldname = 'DEPT'.
  ls_fcat-coltext   = 'Department'.
  APPEND ls_fcat TO gt_fcat.

  ls_fcat-fieldname = 'SALARY'.
  ls_fcat-coltext   = 'Salary'.
  ls_fcat-no_out    = 'X'. "Hide initially
  APPEND ls_fcat TO gt_fcat.
ENDFORM.

3. Displaying the ALV

Call SET_TABLE_FOR_FIRST_DISPLAY. Pass the layout structure, field catalog, and output table.

FORM display_alv .
  DATA: ls_layout TYPE lvc_s_layo.
  ls_layout-zebra = 'X'.
  ls_layout-cwidth_opt = 'X'.

  CALL METHOD lo_grid->set_table_for_first_display
    EXPORTING
      is_layout       = ls_layout
    CHANGING
      it_outtab       = gt_employees
      it_fieldcatalog = gt_fcat.
ENDFORM.

4. Screen Flow Logic

Ensure the logic is triggered in the PBO (Process Before Output) of your screen.

PROCESS BEFORE OUTPUT.
  MODULE status_set.
  MODULE data_fetch.
  MODULE alv_render.

PROCESS AFTER INPUT.
  MODULE user_action.

Refreshing Data

To update the display without reinitializing the grid, use REFRESH_TABLE_DISPLAY.

FORM refresh_grid .
  DATA: ls_stable TYPE lvc_s_stbl.
  ls_stable-row = 'X'.
  ls_stable-col = 'X'.

  CALL METHOD lo_grid->refresh_table_display
    EXPORTING
      is_stable = ls_stable.
ENDFORM.

Handling Events (Interaction)

OOALV becomes powerful when reacting to user actions like toolbar clicks or data changes.

Defining the Event Handler

Create a local class to handle events raised by CL_GUI_ALV_GRID.

CLASS lcl_handler DEFINITION.
  PUBLIC SECTION.
    METHODS: on_toolbar        FOR EVENT toolbar OF cl_gui_alv_grid
                             IMPORTING e_object,
             on_user_command  FOR EVENT user_command OF cl_gui_alv_grid
                             IMPORTING e_ucomm.
ENDCLASS.

CLASS lcl_handler IMPLEMENTATION.
  METHOD on_toolbar.
    " Add a custom button
    DATA: ls_btn TYPE stb_button.
    ls_btn-function  = 'RELOAD'.
    ls_btn-icon      = icon_refresh.
    ls_btn-quickinfo = 'Reload Data'.
    APPEND ls_btn TO e_object->mt_toolbar.
  ENDMETHOD.

  METHOD on_user_command.
    CASE e_ucomm.
      WHEN 'RELOAD'.
        PERFORM fetch_new_data.
        PERFORM refresh_grid.
    ENDCASE.
  ENDMETHOD.
ENDCLASS.

Registering the Handler

Instantiate the handler and link it to the grid instance using SET HANDLER.

DATA: go_handler TYPE REF TO lcl_handler.

FORM register_events .
  CREATE OBJECT go_handler.
  SET HANDLER go_handler->on_toolbar       FOR lo_grid.
  SET HANDLER go_handler->on_user_command  FOR lo_grid.
ENDFORM.

Editing Cells and Styles

To make specific cells editable while keeping others read-only, use the STYLE table in your data structure.

1. Add a field t_style of type LVC_T_STYL to your data structure.
2. Map this field in the layout: ls_layout-stylefname = 'T_STYLE'.
3. Populate the style table for rows where editing is allowed.

FORM set_editable_styles .
  DATA: ls_style TYPE lvc_s_styl.
  LOOP AT gt_employees ASSIGNING FIELD-SYMBOL(<fs_emp>).
    IF <fs_emp>-dept = 'IT'. " Only IT department rows editable
      CLEAR ls_style.
      ls_style-fieldname = 'SALARY'.
      ls_style-style     = cl_gui_alv_grid=>mc_style_enabled.
      INSERT ls_style INTO TABLE <fs_emp>-t_style.
    ENDIF.
  ENDLOOP.
ENDFORM.

Excluding Standard Buttons

To hide specific toolbar buttons (like Insert Row or Delete Row), populate an UI_FUNCTIONS table with the constants from CL_GUI_ALV_GRID.

FORM exclude_buttons .
  DATA: lt_exclude TYPE ui_functions.
  APPEND cl_gui_alv_grid=>mc_fc_loc_delete_row TO lt_exclude.
  APPEND cl_gui_alv_grid=>mc_fc_loc_insert_row TO lt_exclude.
  
  CALL METHOD lo_grid->set_table_for_first_display
    EXPORTING
      it_toolbar_excluding = lt_exclude
    " ... other params
ENDFORM.